Sometimes BMW is too thorough...

[Keith Turner <kturner@xxxxxxxxxxxxx>]

  I have a 88 325i convertible.  A week or so ago, I turned on the rear 
window defogger, and almost immediately turned it back off because of a 
weird smell.  Today I decided to take it apart and see what was causing the 
smell.  In order to get to it, the rear seat had to come out, so I put the 
top down to make that job easier. The defogger is in a plastic housing that 
I took apart, and saw a leaf or two sitting on top of the 2 heating coils. 
 Ahhh, the source of the smell.  Removed the leaves and turned the defogger 
on. Waited a minute and nothing happened, no fan or anything. So I started 
checking voltages, swapping relays, and cleaning grounds. Still nothing, so 
I went to the switch in the dash and repeated the previous. Still nothing. 
 One thing that really struck me as odd was the lack of a ground on the 
relay.  So I grabbed the Bentley and looked up the wiring diagram.

  Well, damn if BMW didn't route the ground wire for the relay through a 
switch that was tripped by the top being down!!  Sometimes overengineering 
is really a PITA!

Keith.
88 325iC
77 320i

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